From 18131e80fbf47d2f9e8a45a43d0df64ecf694041 Mon Sep 17 00:00:00 2001
From: Eric <luv.ilho@gmail.com>
Date: Tue, 9 Mar 2021 14:21:41 -0800
Subject: [PATCH] Wireless Wiretap System using 2x ESP32, INMP441 & MAX98357A

---
 .../Client_INMP441/Client_INMP441.ino         | 113 ++++++
 .../Server_MAX98357A_TTGO/Free_Fonts.h        | 379 ++++++++++++++++++
 .../Server_MAX98357A_TTGO.ino                 | 156 +++++++
 3 files changed, 648 insertions(+)
 create mode 100644 ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Client_INMP441/Client_INMP441.ino
 create mode 100644 ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Free_Fonts.h
 create mode 100644 ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Server_MAX98357A_TTGO.ino

diff --git a/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Client_INMP441/Client_INMP441.ino b/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Client_INMP441/Client_INMP441.ino
new file mode 100644
index 0000000..913faa6
--- /dev/null
+++ b/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Client_INMP441/Client_INMP441.ino
@@ -0,0 +1,113 @@
+#include <WiFi.h>
+#include <ArduinoWebsockets.h>
+#include "driver/i2s.h"
+
+#define I2S_WS_RX  27
+#define I2S_SCK_RX 14
+#define I2S_SD_RX  12
+
+#define I2S_PORT I2S_NUM_1
+#define I2S_SAMPLE_RATE   (16000)
+#define I2S_SAMPLE_BITS   (32)
+#define I2S_READ_LEN      (1024)
+
+const char* ssid = "ESP32-THAT-PROJECT";
+const char* password = "California";
+
+const char* websockets_server_host = "192.168.4.1";
+const uint16_t websockets_server_port = 8888;
+
+TaskHandle_t i2sADCHandler = NULL;
+
+using namespace websockets;
+WebsocketsClient client;
+
+const i2s_config_t i2s_config_rx = {
+  .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX),
+  .sample_rate = I2S_SAMPLE_RATE,
+  .bits_per_sample = i2s_bits_per_sample_t(I2S_SAMPLE_BITS),
+  .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
+  .communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
+  .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1, // default interrupt priority
+  .dma_buf_count = 32,
+  .dma_buf_len = 64
+};
+
+const i2s_pin_config_t pin_config_rx = {
+  .bck_io_num = I2S_SCK_RX,
+  .ws_io_num = I2S_WS_RX,
+  .data_out_num = I2S_PIN_NO_CHANGE,
+  .data_in_num = I2S_SD_RX
+};
+
+void setup() {
+  Serial.begin(115200);
+  start_to_connect();
+}
+
+void start_to_connect(){
+  WiFi.begin(ssid, password);
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println("");
+  Serial.println("WiFi connected");
+  Serial.println("Socket Connecting");
+  
+  client.onEvent(onEventsCallback);
+  while(!client.connect(websockets_server_host, websockets_server_port, "/")){
+    delay(500);
+    Serial.print(".");
+  }
+
+  Serial.println("Socket Connected!"); 
+}
+
+void i2s_adc_data_scale(uint8_t * d_buff, uint8_t* s_buff, uint32_t len)
+{
+    uint32_t j = 0;
+    uint32_t dac_value = 0;
+    for (int i = 0; i < len; i += 2) {
+        dac_value = ((((uint16_t) (s_buff[i + 1] & 0xf) << 8) | ((s_buff[i + 0]))));
+        d_buff[j++] = 0;
+        d_buff[j++] = dac_value * 256 / 2048 ;
+    }
+}
+
+static void i2s_adc_task(void *arg)
+{
+    i2s_driver_install(I2S_NUM_1, &i2s_config_rx, 0, NULL);
+    i2s_set_pin(I2S_NUM_1, &pin_config_rx);
+
+    int i2s_read_len = I2S_READ_LEN;
+    size_t bytes_read;
+
+    char* i2s_read_buff = (char*) calloc(i2s_read_len, sizeof(char));
+    uint8_t* flash_write_buff = (uint8_t*) calloc(i2s_read_len, sizeof(char));
+
+    while (1) {
+        i2s_read(I2S_PORT, (void*) i2s_read_buff, i2s_read_len, &bytes_read, portMAX_DELAY);
+        i2s_adc_data_scale(flash_write_buff, (uint8_t*)i2s_read_buff, i2s_read_len);
+        client.sendBinary((const char*)flash_write_buff, i2s_read_len);
+        ets_printf("Never Used Stack Size: %u\n", uxTaskGetStackHighWaterMark(NULL));
+    }
+    
+    free(i2s_read_buff);
+    i2s_read_buff = NULL;
+    free(flash_write_buff);
+    flash_write_buff = NULL;
+}
+
+void loop() {
+}
+
+void onEventsCallback(WebsocketsEvent event, String data) {
+    if(event == WebsocketsEvent::ConnectionOpened) {
+        Serial.println("Connnection Opened");
+        xTaskCreate(i2s_adc_task, "i2s_adc_task", 4096, NULL, 1, &i2sADCHandler);
+    } else if(event == WebsocketsEvent::ConnectionClosed) {
+        Serial.println("Connnection Closed");
+        ESP.restart();
+    }
+}
diff --git a/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Free_Fonts.h b/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Free_Fonts.h
new file mode 100644
index 0000000..7c0a264
--- /dev/null
+++ b/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Free_Fonts.h
@@ -0,0 +1,379 @@
+// Attach this header file to your sketch to use the GFX Free Fonts. You can write
+// sketches without it, but it makes referencing them easier.
+
+// This calls up ALL the fonts but they only get loaded if you actually
+// use them in your sketch.
+//
+// No changes are needed to this header file unless new fonts are added to the
+// library "Fonts/GFXFF" folder.
+//
+// To save a lot of typing long names, each font can easily be referenced in the
+// sketch in three ways, either with:
+//
+//    1. Font file name with the & in front such as &FreeSansBoldOblique24pt7b
+//       an example being:
+//
+//       tft.setFreeFont(&FreeSansBoldOblique24pt7b);
+//
+//    2. FF# where # is a number determined by looking at the list below
+//       an example being:
+//
+//       tft.setFreeFont(FF32);
+//
+//    3. An abbreviation of the file name. Look at the list below to see
+//       the abbreviations used, for example:
+//
+//       tft.setFreeFont(FSSBO24)
+//
+//       Where the letters mean:
+//       F = Free font
+//       M = Mono
+//      SS = Sans Serif (double S to distinguish is form serif fonts)
+//       S = Serif
+//       B = Bold
+//       O = Oblique (letter O not zero)
+//       I = Italic
+//       # =  point size, either 9, 12, 18 or 24
+//
+//  Setting the font to NULL will select the GLCD font:
+//
+//      tft.setFreeFont(NULL); // Set font to GLCD
+
+
+#ifdef LOAD_GFXFF // Only include the fonts if LOAD_GFXFF is defined in User_Setup.h
+
+// Use these when printing or drawing text in GLCD and high rendering speed fonts
+// Call up the font using tft.setTextFont()
+#define GFXFF 1
+#define GLCD  0
+#define FONT2 2
+#define FONT4 4
+#define FONT6 6
+#define FONT7 7
+#define FONT8 8
+
+// Use the following when calling tft.setFreeFont()
+//
+// Reserved for GLCD font  // FF0
+//
+
+#define TT1 &TomThumb
+
+#define FM9 &FreeMono9pt7b
+#define FM12 &FreeMono12pt7b
+#define FM18 &FreeMono18pt7b
+#define FM24 &FreeMono24pt7b
+
+#define FMB9 &FreeMonoBold9pt7b
+#define FMB12 &FreeMonoBold12pt7b
+#define FMB18 &FreeMonoBold18pt7b
+#define FMB24 &FreeMonoBold24pt7b
+
+#define FMO9 &FreeMonoOblique9pt7b
+#define FMO12 &FreeMonoOblique12pt7b
+#define FMO18 &FreeMonoOblique18pt7b
+#define FMO24 &FreeMonoOblique24pt7b
+
+#define FMBO9 &FreeMonoBoldOblique9pt7b
+#define FMBO12 &FreeMonoBoldOblique12pt7b
+#define FMBO18 &FreeMonoBoldOblique18pt7b
+#define FMBO24 &FreeMonoBoldOblique24pt7b
+
+#define FSS9 &FreeSans9pt7b
+#define FSS12 &FreeSans12pt7b
+#define FSS18 &FreeSans18pt7b
+#define FSS24 &FreeSans24pt7b
+
+#define FSSB9 &FreeSansBold9pt7b
+#define FSSB12 &FreeSansBold12pt7b
+#define FSSB18 &FreeSansBold18pt7b
+#define FSSB24 &FreeSansBold24pt7b
+
+#define FSSO9 &FreeSansOblique9pt7b
+#define FSSO12 &FreeSansOblique12pt7b
+#define FSSO18 &FreeSansOblique18pt7b
+#define FSSO24 &FreeSansOblique24pt7b
+
+#define FSSBO9 &FreeSansBoldOblique9pt7b
+#define FSSBO12 &FreeSansBoldOblique12pt7b
+#define FSSBO18 &FreeSansBoldOblique18pt7b
+#define FSSBO24 &FreeSansBoldOblique24pt7b
+
+#define FS9 &FreeSerif9pt7b
+#define FS12 &FreeSerif12pt7b
+#define FS18 &FreeSerif18pt7b
+#define FS24 &FreeSerif24pt7b
+
+#define FSI9 &FreeSerifItalic9pt7b
+#define FSI12 &FreeSerifItalic12pt7b
+#define FSI19 &FreeSerifItalic18pt7b
+#define FSI24 &FreeSerifItalic24pt7b
+
+#define FSB9 &FreeSerifBold9pt7b
+#define FSB12 &FreeSerifBold12pt7b
+#define FSB18 &FreeSerifBold18pt7b
+#define FSB24 &FreeSerifBold24pt7b
+
+#define FSBI9 &FreeSerifBoldItalic9pt7b
+#define FSBI12 &FreeSerifBoldItalic12pt7b
+#define FSBI18 &FreeSerifBoldItalic18pt7b
+#define FSBI24 &FreeSerifBoldItalic24pt7b
+
+#define FF0 NULL //ff0 reserved for GLCD
+#define FF1 &FreeMono9pt7b
+#define FF2 &FreeMono12pt7b
+#define FF3 &FreeMono18pt7b
+#define FF4 &FreeMono24pt7b
+
+#define FF5 &FreeMonoBold9pt7b
+#define FF6 &FreeMonoBold12pt7b
+#define FF7 &FreeMonoBold18pt7b
+#define FF8 &FreeMonoBold24pt7b
+
+#define FF9 &FreeMonoOblique9pt7b
+#define FF10 &FreeMonoOblique12pt7b
+#define FF11 &FreeMonoOblique18pt7b
+#define FF12 &FreeMonoOblique24pt7b
+
+#define FF13 &FreeMonoBoldOblique9pt7b
+#define FF14 &FreeMonoBoldOblique12pt7b
+#define FF15 &FreeMonoBoldOblique18pt7b
+#define FF16 &FreeMonoBoldOblique24pt7b
+
+#define FF17 &FreeSans9pt7b
+#define FF18 &FreeSans12pt7b
+#define FF19 &FreeSans18pt7b
+#define FF20 &FreeSans24pt7b
+
+#define FF21 &FreeSansBold9pt7b
+#define FF22 &FreeSansBold12pt7b
+#define FF23 &FreeSansBold18pt7b
+#define FF24 &FreeSansBold24pt7b
+
+#define FF25 &FreeSansOblique9pt7b
+#define FF26 &FreeSansOblique12pt7b
+#define FF27 &FreeSansOblique18pt7b
+#define FF28 &FreeSansOblique24pt7b
+
+#define FF29 &FreeSansBoldOblique9pt7b
+#define FF30 &FreeSansBoldOblique12pt7b
+#define FF31 &FreeSansBoldOblique18pt7b
+#define FF32 &FreeSansBoldOblique24pt7b
+
+#define FF33 &FreeSerif9pt7b
+#define FF34 &FreeSerif12pt7b
+#define FF35 &FreeSerif18pt7b
+#define FF36 &FreeSerif24pt7b
+
+#define FF37 &FreeSerifItalic9pt7b
+#define FF38 &FreeSerifItalic12pt7b
+#define FF39 &FreeSerifItalic18pt7b
+#define FF40 &FreeSerifItalic24pt7b
+
+#define FF41 &FreeSerifBold9pt7b
+#define FF42 &FreeSerifBold12pt7b
+#define FF43 &FreeSerifBold18pt7b
+#define FF44 &FreeSerifBold24pt7b
+
+#define FF45 &FreeSerifBoldItalic9pt7b
+#define FF46 &FreeSerifBoldItalic12pt7b
+#define FF47 &FreeSerifBoldItalic18pt7b
+#define FF48 &FreeSerifBoldItalic24pt7b
+
+// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+// Now we define "s"tring versions for easy printing of the font name so:
+//   tft.println(sFF5);
+// will print
+//   Mono bold 9
+// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+#define sFF0 "GLCD"
+#define sTT1 "Tom Thumb"
+#define sFF1 "Mono 9"
+#define sFF2 "Mono 12"
+#define sFF3 "Mono 18"
+#define sFF4 "Mono 24"
+
+#define sFF5 "Mono bold 9"
+#define sFF6 "Mono bold 12"
+#define sFF7 "Mono bold 18"
+#define sFF8 "Mono bold 24"
+
+#define sFF9 "Mono oblique 9"
+#define sFF10 "Mono oblique 12"
+#define sFF11 "Mono oblique 18"
+#define sFF12 "Mono oblique 24"
+
+#define sFF13 "Mono bold oblique 9"
+#define sFF14 "Mono bold oblique 12"
+#define sFF15 "Mono bold oblique 18"
+#define sFF16 "Mono bold oblique 24" // Full text line is too big for 480 pixel wide screen
+
+#define sFF17 "Sans 9"
+#define sFF18 "Sans 12"
+#define sFF19 "Sans 18"
+#define sFF20 "Sans 24"
+
+#define sFF21 "Sans bold 9"
+#define sFF22 "Sans bold 12"
+#define sFF23 "Sans bold 18"
+#define sFF24 "Sans bold 24"
+
+#define sFF25 "Sans oblique 9"
+#define sFF26 "Sans oblique 12"
+#define sFF27 "Sans oblique 18"
+#define sFF28 "Sans oblique 24"
+
+#define sFF29 "Sans bold oblique 9"
+#define sFF30 "Sans bold oblique 12"
+#define sFF31 "Sans bold oblique 18"
+#define sFF32 "Sans bold oblique 24"
+
+#define sFF33 "Serif 9"
+#define sFF34 "Serif 12"
+#define sFF35 "Serif 18"
+#define sFF36 "Serif 24"
+
+#define sFF37 "Serif italic 9"
+#define sFF38 "Serif italic 12"
+#define sFF39 "Serif italic 18"
+#define sFF40 "Serif italic 24"
+
+#define sFF41 "Serif bold 9"
+#define sFF42 "Serif bold 12"
+#define sFF43 "Serif bold 18"
+#define sFF44 "Serif bold 24"
+
+#define sFF45 "Serif bold italic 9"
+#define sFF46 "Serif bold italic 12"
+#define sFF47 "Serif bold italic 18"
+#define sFF48 "Serif bold italic 24"
+
+#else // LOAD_GFXFF not defined so setup defaults to prevent error messages
+
+// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+// Free fonts are not loaded in User_Setup.h so we must define all as font 1
+// to prevent compile error messages
+// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+#define GFXFF 1
+#define GLCD  1
+#define FONT2 2
+#define FONT4 4
+#define FONT6 6
+#define FONT7 7
+#define FONT8 8
+
+#define TT1 1
+
+#define FF0 1
+#define FF1 1
+#define FF2 1
+#define FF3 1
+#define FF4 1
+#define FF5 1
+#define FF6 1
+#define FF7 1
+#define FF8 1
+#define FF9 1
+#define FF10 1
+#define FF11 1
+#define FF12 1
+#define FF13 1
+#define FF14 1
+#define FF15 1
+#define FF16 1
+#define FF17 1
+#define FF18 1
+#define FF19 1
+#define FF20 1
+#define FF21 1
+#define FF22 1
+#define FF23 1
+#define FF24 1
+#define FF25 1
+#define FF26 1
+#define FF27 1
+#define FF28 1
+#define FF29 1
+#define FF30 1
+#define FF31 1
+#define FF32 1
+#define FF33 1
+#define FF34 1
+#define FF35 1
+#define FF36 1
+#define FF37 1
+#define FF38 1
+#define FF39 1
+#define FF40 1
+#define FF41 1
+#define FF42 1
+#define FF43 1
+#define FF44 1
+#define FF45 1
+#define FF46 1
+#define FF47 1
+#define FF48 1
+
+#define FM9  1
+#define FM12 1
+#define FM18 1
+#define FM24 1
+
+#define FMB9  1
+#define FMB12 1
+#define FMB18 1
+#define FMB24 1
+
+#define FMO9  1
+#define FMO12 1
+#define FMO18 1
+#define FMO24 1
+
+#define FMBO9  1
+#define FMBO12 1
+#define FMBO18 1
+#define FMBO24 1
+
+#define FSS9  1
+#define FSS12 1
+#define FSS18 1
+#define FSS24 1
+
+#define FSSB9  1
+#define FSSB12 1
+#define FSSB18 1
+#define FSSB24 1
+
+#define FSSO9  1
+#define FSSO12 1
+#define FSSO18 1
+#define FSSO24 1
+
+#define FSSBO9  1
+#define FSSBO12 1
+#define FSSBO18 1
+#define FSSBO24 1
+
+#define FS9  1
+#define FS12 1
+#define FS18 1
+#define FS24 1
+
+#define FSI9  1
+#define FSI12 1
+#define FSI19 1
+#define FSI24 1
+
+#define FSB9  1
+#define FSB12 1
+#define FSB18 1
+#define FSB24 1
+
+#define FSBI9  1
+#define FSBI12 1
+#define FSBI18 1
+#define FSBI24 1
+
+#endif // LOAD_GFXFF
diff --git a/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Server_MAX98357A_TTGO.ino b/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Server_MAX98357A_TTGO.ino
new file mode 100644
index 0000000..65e1404
--- /dev/null
+++ b/ESP32_MICROPHONE/Wiretap_INMP441_MAX98357A_via_websocket/Server_MAX98357A_TTGO/Server_MAX98357A_TTGO.ino
@@ -0,0 +1,156 @@
+#include <SPI.h>
+#include <ArduinoWebsockets.h>
+#include <WiFi.h>
+#include <TFT_eSPI.h>
+#include "driver/i2s.h"
+#include "Free_Fonts.h"
+
+#define I2S_WS_TX  12
+#define I2S_SCK_TX 13
+#define I2S_DATA_OUT_TX  15
+
+#define I2S_PORT I2S_NUM_0
+#define I2S_SAMPLE_RATE   (16000)
+#define I2S_SAMPLE_BITS   (32)
+#define UPDATE_INTERVAL   (500)
+
+const char* ssid = "ESP32-THAT-PROJECT";
+const char* password = "California";
+
+using namespace websockets;
+WebsocketsServer server;
+WebsocketsClient client;
+
+TFT_eSPI tft = TFT_eSPI();
+TFT_eSprite graph = TFT_eSprite(&tft);
+
+const i2s_config_t i2s_config_tx = {
+  .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_TX),
+  .sample_rate = I2S_SAMPLE_RATE,
+  .bits_per_sample = i2s_bits_per_sample_t(I2S_SAMPLE_BITS),
+  .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
+  .communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
+  .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
+  .dma_buf_count = 32,
+  .dma_buf_len = 64
+};
+
+const i2s_pin_config_t pin_config_tx = {
+  .bck_io_num = I2S_SCK_TX,
+  .ws_io_num = I2S_WS_TX,
+  .data_out_num = I2S_DATA_OUT_TX,
+  .data_in_num = I2S_PIN_NO_CHANGE
+};
+
+TaskHandle_t drawGraphTaskHandler = NULL;
+
+unsigned long last_update_sent = 0;
+bool isConnected; 
+static int sampleValue;
+
+void setup() {
+  Serial.begin(115200);
+  WiFi.softAP(ssid, password);
+  server.listen(8888);
+  
+  displayInit();
+  readyScreen();
+
+  xTaskCreate(server_task, "server_task", 4096, NULL, 1, NULL);
+}
+static void draw_graph_task(void *arg)
+{
+  int preHeight = 0;
+
+  while(1){
+    if(isConnected){
+      int calcHeight = sampleValue;
+      graph.drawLine(tft.width() - 2, preHeight, tft.width() - 1, calcHeight, 1);
+      preHeight = calcHeight;
+      tft.setBitmapColor(TFT_WHITE, TFT_BLACK);
+      graph.pushSprite(0, 0);
+      graph.scroll(-2, 0);
+    }else{
+      vTaskDelay(100);
+    } 
+  }
+}
+
+static void server_task(void *arg)
+{
+  while(1){
+    if(server.poll()){
+        client = server.accept();
+        i2sInit();
+        last_update_sent = millis();
+        isConnected = true;
+        xTaskCreate(draw_graph_task, "draw_graph_task", 2048, NULL, 1, &drawGraphTaskHandler);
+      }
+
+     if(isConnected && millis() - last_update_sent > UPDATE_INTERVAL) {
+      vTaskDelete(drawGraphTaskHandler);
+      Serial.println("Client disconnected! Uninstall I2S driver");
+      isConnected = false;      
+      i2s_driver_uninstall(I2S_PORT);
+      readyScreen();
+    }
+    vTaskDelay(100);
+  }
+}
+
+void loop() {
+  i2s_write_from_client();
+}
+
+void i2s_write_from_client()
+{   
+  if(client.available()){
+    last_update_sent = millis();
+    client.poll();
+    WebsocketsMessage msg = client.readBlocking();
+    char *buf_ptr = (char*)msg.c_str();
+    int bytes_written = msg.length();
+    i2s_write_bytes(I2S_PORT, buf_ptr, bytes_written, portMAX_DELAY);
+
+    int32_t sample = (int32_t) buf_ptr[3] << 24;
+    sample |=  (int32_t) buf_ptr[2] << 16;
+    sample |= (int32_t) buf_ptr[1] << 8;
+    sample |= (int32_t) buf_ptr[0];   
+
+    sampleValue = map(sample / 100000, -4000, 4000, 0, tft.height());
+  }
+}
+
+void i2sInit(){
+  i2s_driver_install(I2S_PORT, &i2s_config_tx, 0, NULL);
+  i2s_set_pin(I2S_PORT, &pin_config_tx);
+}
+
+void displayInit(){
+  tft.begin();
+  tft.setRotation(1);
+  tft.setTextColor(TFT_WHITE,TFT_BLACK); 
+  tft.fillScreen(TFT_BLACK);
+  graph.setColorDepth(1);
+  graph.createSprite(tft.width(), tft.height());
+  graph.fillSprite(TFT_BLACK);  
+}
+
+void readyScreen(){
+  tft.fillScreen(TFT_BLACK);
+  tft.setTextDatum(TL_DATUM);
+
+  tft.setFreeFont(FF21);
+  tft.setTextColor(TFT_RED, TFT_BLACK);
+  tft.drawString("WIRELESS", 10, 10, GFXFF);
+ 
+  tft.setFreeFont(FF24);
+  tft.setTextColor(TFT_YELLOW, TFT_BLACK);
+  tft.drawString("WIRETAP", 10, 40, GFXFF);
+
+  tft.setFreeFont(FF21);
+  tft.setTextColor(TFT_WHITE, TFT_BLACK);
+  tft.drawString("Waiting for the other side", 0, 95, GFXFF);
+  tft.setFreeFont(FF9);
+  tft.drawString("Version 0.1", 0, 115, GFXFF);
+}